What stops doctors from treating pain?

The lede:

Seven in 10 doctors agree that chronic noncancer pain is undertreated in the U.S.

Nearly half of 150 practicing primary care physicians surveyed said they used nonclinical considerations to determine whether to prescribe opioids to treat such pain. In a recent study by the American Pain Foundation, the doctors ranked regulatory and law enforcement scrutiny as the biggest barriers.

The whole shebang.